Mobile pavement breaker having leaf spring impact tool accelerating means



Aug. 25, 1959 W, H Ewls 2,901,232

LMOBILE PAVEMENT BREAKER HAVING LEAF' SPRING IMPACT TOOL ACCELERATINGMEANS Filed Feb. 6, 1956 5 Sheets-Sheet l w NN NNN R. m W M w E s e 3N Wl $1 .Il Jun m M A m 4 k u. W Y 'v B QW Aug. 25, 1959 W H, LEWls2,901,232

I MOBILE PAVEMENT BREAKER HAVING LEAF SPRING IMPACT TOOL ACCELERATINGMEANS Filed Feb. 6, 1956 5 Sheets-Sheet 2 INVENTOR. W/u mm H ew/5 Aug.25, 1959 W. H.

MOBILE PAVEMENT BR LEWIS EAKER HAVING LEAF SPRING IMPACT TOOLACCELERATING MEANS 5 Sheets-Sheet 3 Filed Feb. 6, 1956 R5 0/ W4, W l HMW m ,4

United States Patent() MOBILE PAVEMENT BREAKER LEAF SPRING MACT TOOLACCELERATING MEANS William H. Lewis, Arcadia, Calif., assignor to`CutcreteV Manufacturing Corp., El Monte, Calif., a corporation offCalifornia Application February 6, 1956, Serial No. 563,664

9 Claims. (Cl. 262--18) The present invention relates generally'to theveldof` road building and' more particularly to a mobile pavementbreaker.

In repairing, replacing or` otherwise servicing paved surfaces such asroads, parking areas, airport runways and the like, it is sometimesnecessary to break up and remove the existing pavement. Thereafter, suchpavement is removed from its original site. Although there exist severaltypes of mobile pavement breaking devices, they are generally expensiveto maintain and service. These heretofore-proposed devices generallyincorporate a heavy breaking hammer which is reciprocated against thepavement several times a minute. This hammer is either hydraulically orpneumatically urged into contact with the pavement, or alternately itmay be raised a sufficient height above the pavement that it will breaksame upon being dropped from such height. Where the pavement breakinghammer is urged under power into contact' With the pavement, the drivingmechanism is subjected to rapid wear because of the severe shocksimparted thereto. Where, on the other hand, the hammer is lifted asuiiicient height above the pavement that it may break same upon beingdropped thereagainst, not only must a large and cumbersome structure beprovided but additionally the number of blows per unit of time which maybe undergone by the hammer -is necessarily limited.

It is a major object of the present invention to provide a novel andimproved mobile pavement breaker which eliminates the disadvantages ofthe existing devices of this nature.

It is a more particular object of the invention to provide a mobilepavement breaker which is inexpensive to construct and maintain ascompared to theretoforeproposed pavement breakers.

Another particular object of the invention is to provide a mobilepavement breaker which is compact in size and light of weight ascompared to existing machines of this type.

A further object of the invention is to provide a mobile pavementbreaker `which delivers a maximum amount of pavement breaking blows perunit of time.

An additional object of the present invention is to provide a mobilepavement breaker of the aforedescribed nature which is mounted upon aself-propelled, steerable, wheeled chassis.

Another object of the invention is to provide a mobile pavement breakerwherein the force with which its pavement breaking hammer is urged intothe pavement may be readily controlled by a simple mechanism.

These and other objects and advantages of the present invention willbecome apparent from the following detailed description, when taken inconjunction with the appended drawings, wherein:

`Figure l is a side elevational view, taken partly in vertical section,showing a preferred form of mobile pavement breaker embodying thepresent invention;

` Figure 2 is a top'plan view lofs'aidV mobile pavement breaker; p

Figure 3 is an enlarged vertical sectionalview ofthe encircledareadesignated` 3 ini Figure. 1";m

Figures 4 and 5 are fragmentaryV enlargedviews showing the operation. ofthe liftingfrneclianisn for the pavement breaking hariuner;

Figure 6 is a front elevationlviw dfsaid mobile pave`` ment breaker; l p

Figure 7` is an enlarged' vertical` sectional viewA taken' on line 7--7of. Figure 1;,a"iid`` p v Figure 8 isa horizontal, viewr' taken alongline 8-8. of Figure 7. p p p Referring tothe` drawings and particularlyFigures 1, 2 and 6 thereof, the preferredformdf, mobile pavement breakerembodying the' present' irive'ritionY includes a wheeled frame FAmovable" overl the pavementV P` to be broken. A pavement breakingAhammer'- H is' mounted at the rear portion of the' frame E forV verticalreciprocal movement relative thereto through a distance designated X-lin Figure 6; The hammer H'is corrected to a powerdriven hammerliftingmeans L( by means of a ilexible element, such as a' cable 22; Thehammer lifting means L includes a crank arm 24 that is rotated bypoweroperated means, such as an internalicornbuston engine. E mounted atthe front" portion` of the frame F. After the hammer H has been liftedto' the top of its stroke by the crank arm 24 itispermitted to movedownwardly under the influenceof gravity; Spring.` means S areinterposedbetween the frame F and the hammer H for accelerating the downwardmotion" of` the latter. The downwardly moving hammer H hits `thepavement P with considerable force so as to.' effect the. breakingthereof. In the preferred form of the mobile pavement breaker, thepavement breaking` hammer H, its lifting.

means L and the spring SV are carried upon an auxiliary frame A, therear portion of which is caused to undergo pivotal movement in ahorizontal plane relative to the main frame F. In this manner, the`hammer H is moved through an arcuate horizontal path relative to therear portion of the main frame F. Referring to Figure 2, this arcuatemotion takes placethrough an angle designated alpha on either side ofthe' longitudinal center line of the frame F. p C

More particularly, the' main frame F includes a pair of side elements 26and 28 which are' interconnected at their front end by a cross-brace 30and at their rear end by a cross-brace 32. A transverse cross-brace 34interconnects the side members adjacent the4 rear portion ofthe engineE. The fro'nt wheelstare` supported at the outer ends of a rigid frontaxle 38. These wheels are each carried by a vertical pivot pin 4 0 fromthe rear end of which extends a steering" lever 42. The" rear ends ofthe steering levers 42 are pivotally attached" to either side of atransverse steering link 44. An actuating lever 46 extends rearwardlyfrom one side of the steering link 46. The rear portion of thisactuating lever 46 is formed with a slot 48 which slidably receivesithefree end of a plunger 50 that is `reciprocally` disposed within ahydraulic steeringV cylinder 52 carried by the' underside of the mainframe F. A flexible l'rydraulic` line 54 extends from one end of thesteering cylinder 52 tb a pump 56` mounted at the rear portion of theframe-F. Therear wheels 58l are mounted by a pair of rear axlesrotatably disposed within a pair of axle housings 60. The* rear axlesare connected to` a conventional diiferential 62' that is interposed*are connected to a second set of pulleys 70 keyed to the drive shaft 72of the engine E by belts 74.

The auxiliary frame A includes an elongated box member.75 that ispivotally secured to. the transverse crossbrace 34 of the mainframe F bya vertical pivot bar 76 at a point adjacent the rear end of the engineE. Referring particularly to Figures 7 and 8, the rear portion ofthe-lower wall 77 of the box member 75 is formed with a longitudinallyextending slot 78. This slot 78 intersects a transversely extending slot80 formed in the upper wall 82 of the rear cross-brace 32. The rearp0rtion of the box member 75 is slidably connected to the rearcross-brace 32 of the frame F by a connector, generally ldesignated 84.This connector 84 includes a pair of rollers 86 and 88v disposed withinthe slots 78 and 80, respectively. These rollers 86 and 88 are journaledby a vertically extending bolt 90. An upper lretainer 92 is interposedbetween the head of the bolt 90 and the upper roller 86 and a lowerretainer 94 is interposed between the lower roller 88 and a nut 96secured to the lower end of the bolt 90. With this arrangement, the rearportion of the auxiliary frame F is free to undergo arcuate movementrelative to the rear portion of the main frame F about a centercorresponding with the center of the pivot bar 76.

The relative motion of the auxiliary frame A relative to the main frameF may be effected by means of a hydraulic cylinder 98 that is affixed tothe underside of the box member 75 and a pair of plunger rods 100 and102 which cooperate with this hydraulic cylinder. The mid-portion ofthis hydraulic cylinder 98 is formed with an upstanding pivot pin 104. Aroller 106 journaled by this pivot pin 104 is slidably disposed within alongitudinally extending slot 108 formed in the lower wall 77 of the boxmember 75. The pair of plunger rods and 102 extend outwardly from thehydraulic cylinder and their outer ends arepivotally secured to the sideelements 26 and 28, respectively, of the main frame F. A pair offlexible hydraulic conduits 110 and 112 extend from the outer ends ofthe hydraulic cylinder 98 to the pump 56. The rear end of the auxiliaryframes box member 75 is formed with a vertically extending guide member114 for the hammer H. The crank arm 24 is disposed above the guidemember 114 and is carried by a horizontal lift- Ing shaft 116. Thehorizonatl lifting shaft 116 is journaled within an opstanding post 118formed at the rear portion of the obx member 75, as shown in Figures 3,4 and 5. The rear end of thisy lifting shaft 116 is keyed to a sprocket119 and a chain 120 interconnects this sprocket 119 with a secondsprocket 122 which is keyed to the output shaft 124 of a reduction gearbox 126. The reduction gear box 126 is driven by the engine E through atake-olf shaft 128. A clutch 130 and a pair of univer-y sal joints 132and 134 are provided for this take-off shaft, as shown in Figures l and2. The pump 56 is driven through the reduction gear box 126.

Referring again to Figures 3, 4 and 5, a driving element 136 is keyed tothe rear end of the lifting shaft 116 by a plurality of bolts 13S. Theouter portion of this driving element 136 is formed with a pair ofnotches 142, one of which is adapted to abut a driving pin 144 extendingfrom the intermediate portion of the crank arm 24. A covered sheave 146is carried by the outer end of the crank arm 24. This sheave 146encompasses the upper end of the looped cable 22, the lower end of thelatter passing throughythe upper portion of the hammer H, as indicatedin Figure 6. Referring to Figure 2, it will be observed that the axis ofrotation of the lifting shaft 116 is transversely offset from thevertical center line of the hammer H a distance approximating the lengthof the crank arm 24.

The spring means S Ywill preferably include a multileaf spring 148having its mid-portion rigidly affixed by a clamp 150 to a horizontalbar 15,2 disposed within the box member 75 of the auxiliary frame. Thebar 152 iS f f "2,901,232y

[L pivotally supported upon a shaft 153 having its ends carried by thesides of the box member 75, as shown in Figure 7. The rear end of theleaf spring 148 is carried by the lower end of a vertically extendingadjustment post 154. This adjustment post is engaged with a nut member156 secured to the upper wall of the box member 75. The adjustment post154 may be provided with a hand crank 157. The front portion of the leafspring 148 extends through a vertical slot 158 into the confines of theguide member 114. n The operation of the aforedescribcd mobile pavementbreaker is controlled by an operator (not shown) seated Y in aconventional seat or saddle 160 disposed at the rear portion of the boxmember 75. The operator is pro'- vided with a control panel 162. Thedevice may be driven lto the pavement breaking site under its own powerif desired. At this time, the take-off shaft 128 will be declutched fromthe engine E. When the pavement breaking operation is to begin, the mainframe F will be stopped and the clutch 138 will be actuated so a-s toeffect rotation of the take-off shaft 128. The rotation of the take-olfshaft 128 will be transferred to the lifting shaft 116 by means of thesprockets 119 and 122 and the chain 128. Rotation of the lifting shaft116 will be transferred to the crank arm 24 by means of the drivingelement 136, as indicated in Figures 4 and 5. When the crank arm 24reaches a position approximating that of Figure 5, the hammer H willhave been lifted to the top of its vertical travel. Thereafter, thehammer will be free to fall under the inuenec of gravity. The downwardmotion of the hammer H at this time will be accelerated considerably bythe spring 148. Accordingly, by the time the lower end of the hammer Hcontacts the pavement P it will be travelling at considerable speed soas to deliver a powerful blow against the pavement. As the hammer Hundergoes vertical reciprocation relative to the pavement P, the rearend of the auxiliary frame A will undergo concurrent pivotal movementrelative to the rear portion of the main frame F. In this man. ner theentire pavement area adjacent the rear portion of the main frame F maybe broken. The operator will preferably be provided with sufficientcontrols for adequately `adjusting the speed and force with which thehammer is operated as well as the speed at which the auxiliary frame Amoves relative to the main frame F. The entire device may be moved overthe surface of the pavement to be broken under its own power.Accordingly, once the pavement adjacent the rear portion of the mainframe F has been broken, the device may be moved forward under its ownpower so as to break the next portion of the pavement. It should beespecially noted that neither the cable 22 nor the spring 148 willtransfer the impact shock of the hammer H to either of the frames F andA.

While there has been shown and described hereinbefore what is presentlyconsidered to be the preferred embodiment of the present invention, itwill be apparent that various modifications and changes may be madethereto without departing from the spirit of the invention 0r the scopeof the following claims.

1 claim:

1. A mobile pavement breaker, comprising: a Wheeled frame movable oversaid pavement; a crank mounted upon said frame for rotation in avertical plane; poweroperated means on said frame for effecting rotationof said crank; a guide member formed on said frame below said crank inapproximate vertical alignment therewith; a pavement-breaking hammerslidably carried by said guide member for vertical reciprocal movementrelative to said pavement, said hammer being offset from the axis ofrotation of said crank; means drivingly connecting said power-operatedmeans and said crank during an upstroke of said crank, said meansdisconnecting said power-operated means from said crank during a down,

stroke of the latter; a flexible element interconnecting the free end ofsaid crank and said hammer whereby said crank will raise said hammerduring its upstroke; and a horizontal leaf spring interposed betweensaid frame and said hammer with its free end extending into the coniinesof said guide member for abutting said hammer, said spring means beingdeformed by upward movement of `said hammer and said spring meansreturning towards its normal configuration during a downstroke of saidhammer to thereby accelerate the downward movement of said hammer.

2. A mobile pavement breaker, comprising: a wheeled frame movable oversaid pavement; a crank mounted upon said frame for rotation in avertical plane; power-operated means on said frame for effectingrotation of said crank; a guide member formed on said frame below saidcrank in approximate vertical alignment therewith; a pavement-breakinghammer slidably carried by said guide member for vertical reciprocalmovement relative to said pavement, said hammer being olfset from theaxis of rotation of said crank; means drivingly connecting saidpower-operated means and said crank during an upstroke of saidV crank,said means disconnecting said power-operated means from said crankduring a downstroke of the latter; a iiexible element interconnectingthe free end of said crank and said hammer whereby said crank will raisesaid hammer during its upstroke; a horizontal leaf spring having itsintermediate portion pivotally secured to said frame with one of itsends extending into the confines of said guide member so as to abut saidhammer, said spring means being deformed by upward movement of saidhammer and said spring means returning towards its normal configurationduring downward movement of `said hammer to thereby accelerate thedownward movement of said hammer; and adjustment means interposedbetween the opposite end of said leaf spring and said frame for varyingthe elevation of said opposite end to thereby control the amount offorce applied by said spring to said hammer.

3. A mobile pavement breaker, comprising: a wheeled frame movable oversaid pavement; a power-operated horizontal lifting shaft carried by saidframe; a driving element keyed to said shaft; a crank journaled on saidshaft; a driving pin formed on the intermediate portion of said crankand engageable with said driving element whereby said driving elementwill impart rotation to said crank in one direction; a guide memberformed on said frame below said crank in approximate vertical alignmenttherewith; a pavement-breaking hammer slidably earned by said guidemember for vertical reciprocal movement relative to said pavement, saidhammer being olset from the axis of rotation of said crank; a flexibleelement interconnecting the free end of said crank and said hammerwhereby said crank will raise said hammer during its upstroke; and ahorizontal leaf spring interposed between said frame and said hammerwith its free end extendmg into the confines of said guide member forabutting said hammer, said spring means being deformed by upwardmovement of said hammer and said spring means returning toward itsnormal configuration during a downstroke of said hammer to therebyaccelerate the downward movement of said hammer.

4. A mobile pavement breaker, comprising: a wheeled frame movable oversaid pavement; a poweroperated horizontal lifting shaft carried by saidframe; a driving element keyed to said shaft; a crank journaled on saidshaft; a driving pin formed on the intermediate portion of said crankand engageable with said driving element whereby said driving elementwill impart rotation to said crank in one direction; a guide memberformed on said frame below said crank in approximate vertical alignmenttherewith; a pavement-breaking hammer slidably carried by said guidemember for vertical reciprocal movement relative to said pavement, said`hammer being olfset from the axis of rotation of said crank; a flexibleelement interconnecting the free end of said crank and said hammerwhereby said crank will raise said hammer during its upstroke; ahorizontal leaf spring having its intermediate portion pivotally securedto said frame with one of its ends extending into the contines of saidguide member so as to abut said hammer, said spring means being deformedby upward movement of said hammer and said spring means returningtowards its normal configuration during downward movement of said hammerto thereby accelerate the downward movement of said hammer; andadjustment means interposed between the opposite end of said leaf springand said frame for varying the elevation of said opposite end to therebycontrol the amount of force applied by said spring to said hammer.

5. A mobile pavement breaker, comprising: a wheeled main frame movableover said pavement; an auxiliary frame pivotally supported upon saidmain frame so as to undergo movement relative thereto in a horizontalplane; engine means on one of said frames; a crank mounted on saidauxiliary frame for rotation in a vertical plane; force-transfer meansconnected to said engine means; a guide member formed on said auxiliaryframe below said crank; a pavement-breaking hammer slidably supported bysaid guide member for Vertical reciprocal movement relative to saidpavement, said hammer being offset from the axis of rotation of saidcrank; means drivingly connecting said force-transfer means and saidcrank during an upstroke of said crank, said means disconnecting saidforce-transfer means from said crank during a downstroke of the latter;a exible element interconnecting the free end of said crank and saidhammer whereby said crank will raise said hammer during an upstroke ofsaid crank; a generally horizontally extending leaf spring interposedbetween said auxiliary frame and said hammer, with one end of said leafspring extending into the contines of said guide member so as to abutsaid hammer, said spring being deformed upwardly by upward movement ofsaid hammer and said spring returning towards its normal configurationduring a downstroke so as to thereby accelerate the downward movement ofsaid hammer; and second force-transfer means interposed be'- tween saidengine means and said frames so as to effet said movement of saidauxiliary frame in a horizontal plane concurrent with said verticalmovement of said hammer.

6. A mobile pavement breaker, comprising: a wheeled main frame movablelongitudinally overI said pavement; an auxiliary frame supported uponsaid. main frame so as to undergo movement relative thereto in ahorizontal plane; engine means on one of said frames; a transverselyextending crank mounted on the rear portion of said auxiliary frame forrotation in a vertical plane; force-transfer means operatively connectedto said engine means; a guide member formed on the rear portion of saidauxiliary frame below and in approximate vertical alignment with saidcrank; a pavement breaking hammer slidably supported by said guidemember for vertical reciprocal movement relative to said pavement, saidhammer being transversely olfset from the axis of rotation of saidcrank; means drivingly connectiing said force-transfer means and saidcrank during an upstroke of said crank, said means disconnecting saidforce-transfer means from said crank during a downstroke of the latter;a flexible element interconnecting the free end of said crank and saidhammer whereby said crank will raise said hammer during an upstroke ofsaid crank; a generally horizontally and longitudinally extending leafspring interposed between said auxiliary frame and said hammer with therear end of said leaf spring extending into the confines of said guidemember so as to abut said hammer, said spring being deformed upwardly byupward movement of said hammer and said spring returning towards itsnormalconfiguration during a downstroke of said hammer so as to therebyaccelerate the downward movement of said hammer; and said secondforce-transfer means operatively interposed between said engine meansand said frame so as to effect said movement of said auxiliary frame ina horizontal plane concurrent with said vertical movement of saidhammer.

7. A mobile pavement breaker, comprising: a Wheeled main frame movablelongitudinally over said pavement; an auxiliary frame pivotallysupported upon said main frame so as to undergo swinging movementrelative thereto in a horizontal plane; engine means on one of saidframes; a transversely extending crank mounted on the rear portion ofsaid auxiliary frame for rotation in a vertical plane; force-transfermeans operatively connected to said engine means; a vertically extendingguide member formed on the rear portion of said auxiliary frame be*- lowand in approximate vertical alignment with said crank; a pavementbreaking hammer slidably supported by said guide member for verticalreciprocal movement relative to said pavement, said hammer beingtransversely offset from the axis of rotation of said crank; meansdrivingly connecting said force-transfer means and s'aid crank during anupstroke of said crank, said means disconnecting said force-transfermeans from said crank during'a downstroke of the latter; a fiexibleelement interconnecting the free end of said crank and said hammerwhereby said crank will raise said hammer during an upstroke of saidcrank; a generally horizontally and longitudinally extending leaf springhaving its intermediate portion pivotally secured to said auxiliaryframe with its rear end extending into the confines of said guide memberso as to abut said hammer, said leaf spring being deformed by upwardmovement of said hammer and said spring returning towards its normalconfiguration during downward movement of said hammer to therebyaccelerate the downward movement of said hammer; adjustment meansinterposed between the front end of said leaf spring and said auxiliaryframe for varying the elevation of said front end to thereby control theamount of force applied by said spring to said hammer; and secondforce-transfer means inter- .posed between said engine means and saidframes so as to effect said swinging movement of said auxiliary frameconcurrent with said vertical movement of said hammer.

8. A mobile pavement breaker, comprising: a wheeled main frame movablelongitudinally over said pavement; an auxiliary frame pivotallysupported upon said main frame so as to undergo swinging movementrelative thereto in a horizontal plane; engine means on one of saidframes; a longitudinally and horizontally extending lifting shaftrotatably carried by said auxiliary frame; a driving element keyed tosaid shaft; a transversely extending crank journaled on said liftingshaft; a driving pin formed on the intermediate portion of said crankand engageable with said driving element whereby said driving elementwill impart rotation to said crank in one direction; force-transfermeans connecting said engine means to said lifting shaft so as to effectrotation of the latter; a flexible element interconnecting the free endof said crank and said hammer whereby said crank will raise said hammersolely during an upstroke of said crank; a generally horizontally andlongitudinally extending leaf spring interposed between said auxiliaryframe and said hammer with the rear end of said leaf spring extendinginto the confines of said guide member so as to abut said hammer, saidspring being deformed upwardly by upward movement of said hammer andsaid spring returning towards its normal configuration during adownstroke of said hammer so as to thereby accelerate the downwardmovement of said hammer; and second force-transfer means interposedbetween said engine means and said frames so as to effect saidswingingmovement of said auxiliary frame concurrent with said verticalmovement of said hammer.

9. A mobile pavement breaker, comprising: a Wheeled main frame movablelongitudinally over said pavement; an auxiliary frame pivotallysupported upon said main frame so as to undergo swinging movementrelative thereto in a horizontal plane; engine means on one of saidframes; a longitudinally and horizontally extending lifting shaftcarried by said auxiliary frame; a driving element keyed to said shaft;a transversely extending crank journaled on said lifting shaft; adriving pin formed on the intermediate portion of said crank andengageable with said driving element whereby said driving element impartrotation to said crank solely in one direction; `force-transfer meansconnecting said engine means to said lifting shaft so as to effectrotation of the latter; a exible element interconnecting the free end ofsaid crank and said hammer whereby said crank will raise said hammersolely during an upstroke of said crank; a generally horizontally andlongitudinally extending leaf spring having its intermediate portionpivotally secured to said auxiliary frame with its rear end extendinginto the confines of said guide member so as to abut said hammer, saidspring being deformed by upward movement of said hammer and said springreturning towards its normal configuration during downward movement ofsaid hammer to thereby accelerate the downward movement of said hammer;adjustment means interposed between the front end of said leaf springand said auxiliary frame for varying the elevation of said front end tothereby control the amount of force applied by said spring to saidhammer; and second force-transfer means interposed between said enginemeans and said,

frame so as to effect said swinging movement of said auxiliary frame ina horizontal plane concurrent with said vertical movement of saidhammer.

References Cited in the le of this patent UNITED STATES PATENTS

